Telephone system



TELEPHONE SYSTEM Filed April 29, 1926. 6 Sheets-Sheet 1 F-Ennuunfiuunmi W U" l mnuu Qmunn -Inusrzur Ralph L e zc h Raymond" M iii;

June 18, 1929. RAYMOND 1,717,893

TELEPHONE SYSTEM Filed April 29, 1926 6 Sheets-Sheet 2 70 orsm's.

HEAD an -Inuen EII' June 9- R. L. RAYMOND 1,717,893

TELEPHONE SYSTEM 6 Sheets-Sheet 3 June 18, 1929. RAYMOND 1,717,89 3

TELEPHONE SYSTEM Filed April 29, 1926 6 Sheets-Sheet 4 L h R F 4577-45), b a 112x 1 June 18, 1929. R. L. RAYMOND I 1.717.893

' TELEPHONE SYSTEM Filed April 29, 1926 e Sheets-Sheet 5 33/ JT/ffl r r0 mu L r/msr an.

.Tnusn CII' weigh Raymund I, Wang-i June 18, 1929. RAYMOND 1,717,893

TELEPHONE SYSTEM Filed April 29, 1926 6 Sheets-Sheet 6 I ||HI WIT:

patented June 38, I929.

unirsn stares PATENT oFFica.

RALPH LEIGH RAYMOND, OF TAMPA, FLORIDA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATIO1\T OF DELA- WARE.

TELEPHONE SYSTEM.

Application filecl April 29,

The present invention relates to telephone systems in general, but is concerned more particularly with improved methods of establishing long distance telephone connections between separate telephone-exchanges when certain of them are automatic exchanges.

One object of the invention is the provision of suitable arrangements for relaying ring- .ing current through an intermediate ex change in which switches are operated according to the loop-control system.

Another object is the provision of suitable circuit arrangements whereby, in a system in which ringing current is transmitted over the toll lines, answering supervision is relayed back to a calling operator-when the called subscriber in the distant exchange responds.

In addition to the foregoing main Objects, there are a number of other objects and features, which are more or less incidental to the production of arrangements for carrying out the foregoing, which will be understood upon a further perusal of the specification.

Referring now to the drawings comprising Figs. 1-6, Fig. 1 a trunking diagram showing a general layout of the system, and Figs. 2-6 are circuit drawings, which, when taken in connection with Fig. 1 and in connection with this specification, show a sutficient amount of the apparatus in the system embodying the principles of the invention to enable the invention to be understood.

Referring now particularly to Fig. 1, this drawing shows apparatus located in three exchanges. Exchange #1 is a manual exchange while exchanges #2 and #3 areautomatie exchanges. Exchange #2 is connected directly by means of toll lines with exchanges #1 and #3, but there are no toll lines directly connecting the first and third exchanges.

In addition to the exchanges shown, there may be a number of other exchanges reached by way of toll lines terminating at exchange Also there may be still other exchanges reached by way of trunk lines terminating in exchanges #1. and #3, dependin of course, upon the particular situation in which the trunking system is employed. These latter exchanges are not shown, however, in order to avoid undue complication of the disclosure.

Gne trunk linelX) is shown connecting 1926. Serial No. 105,369.

exchange #1 with exchange #2. This trunk line terminates at the toll board exchange #1 in the jacks J and J and it terminates at the exchange #2 in the jacks J and J, as well as in the repeater R.- It is understood, of course, that a sufiicient number of toll lines, such as X, are provided to handle the tratfic between the exchanges concerned.

Similarly, the toll line Y connects the exchanges #2 and #3. This toll line terminates at exchange #2 in the repeater R and also in the acks J 8 and J At the exchange #3, the toll line Y terminates at the repeater R and at the jacks J and J.

From the above, it is to be understood that the toll lines X and Y can be used manually as well as automatically.

Regarding the provision for the automatic operation of the toll lines, the repeaters It and R in exchange #2 are connected with the first selectors I and I respectively. Siinilarly the repeater R in exchange #3 is coin nectcd with the toll first selector 1*.

In either automatic exchange the first nine levels of the toll first selectors are multipled directly with the corresponding levels ot the local first selectors. In that way, the same local trunking system, as regards the second selectors and connectors, is used for both local calls and for the completion of toll calls.

In the exchange #2, the tenth level of the toll first selectors, instead of connecting to the switchboard of the toll recording ope 'atoras does the tenth level of the local first selectors in either automatic exchange, connects to toll switching selectors such the second selector II. These toll switching selectors have access on their various level to the toll. lines terminating at the switching exchange. For example, the selector II has access on the first level to the toll line X, and other lines, leading to exchange #1 and it has access through its second level to the toll line Y, and others, leading to exchange #3.

Regarding the local trunking in exchange #2, the lines such as that of substation A have access through lineswitches such as LS, to first selectors, such as the first selector I. Asthe exchange #2 is assumed to be of the ten-thousand-line type each of the levels of the selector I with the exception of the tenth level leads to a separate group of second selectors such as the selector II. These second selectors are hundreds selectors and various levels lead to separate groups of connectors, one of which connectors, the connector G, is shown. The connectors in turn have access to the various local lines, such as that of the subscriber at substation A.

It may be here pointed out that in case the exchange #2 is a multi-ofiice exchange the various levels of the first selectors (instead of leading to separate thousand line groups in the same office) lead each to a different oflice of the exchange and terminate there in thousands selectors or hundreds selectors, depending upon the sizes of the individual offices. In this latter case it may be assumed that the toll board is located at the most convenient otfice of the Inulti0ffi0e exchange.

The trunking within the exchange #3 is shown the same as that in exchange #2 except that, since there are no toll lines shown outgoing from exchange #3 to other exchanges, no toll switching selectors are shown, the tenth level of the toll first selectors being left dead.

A separate toll recording operator is provided for each exchange. A manual subscriber desiring a toll connection is connected with the toll recording operator by the answering operator, and an automatic subscriber is connected to the switchboard of the toll recording operator responsive to the dialling of the digit 0. A toll recording operator records such information as may be neces sary and passes it to the toll operator. The calling subscriber is instructed by the recording operator to replace his receiver and wait until he is recalled by the toll operator.

The toll operator may first set up a connection to the calling line, in the case of a calling manual subscriber, but not operate her ringing key, and in the case of an automatic calling subscriber the toll operator may dial the complete number with the exception of the last digit, after which, in either case, she proceeds to extend the connection over the toll line to the desired called line.

In the case of a calling manual subscriber, the toll'operator merely throws her ringing key to signal the calling subscriber when the called subscriber has answered, and in the case of a calling automatic subscriber, the toll operator merely dials the last digit in the number after the called subscriber has responded.

In case the subscriber at substation A in exchange #1 desires to converse with the subscriber at substation A in the exchange #3, the toll operator may complete the connection to the calling line by means of the left hand plug of the cord circuit CC, and then insert the right hand plug of the cord CC into the jack J 3 and dial the digits 0 and 2, followed by the local number of the subscriber at substation A The digit 0 operates the toll first selectorI in exchange #2 to seize a toll switching selector such as the selector II;

the digit 2 operates the selector II to seize a toll line such as Y; and the dialling of the local number of the subscriber at substation A results in a connection being set up which includes the toll first selector I, a second selector, such as 11 and a connector, such as the connector C.

In case the call is for a subscriber whose line terminates in exchange #2, for example, the subscriber at substation A, the toll operator in exchange #1, after having inserted the right hand plug of the cord circuit CC in the jack J merely dials the local directory number of the subscriber at substation A, with the result that the connection is completed through the toll first selector I, a second selector, such as II, and a connector, such as C, to the line of substation A.

It may happen occasionally that the calling subscriber is unable to give the exact number of the called subscriber in which case the toll operator must ring over the toll line to solicit the aid of the operator in the called exchange to ascertain the number and to complete the connection, or to merely inform the calling toll operator of the number of the called subscriber. In the latter case, the calling toll operator releases the connection to the second operators switchboard and then sets up a new connection to the called line in the above manner.

In case the calling operator in exchange #1 desires to speak to the operator in exchange #3, she plugs into a toll line such as X and dials the digits 0 and 2 after which she throws her ringing key to operate the usual drop at the switchboard of the toll operator in exchange #3. It may sometimes happen that the toll lines X and Y are of considerable length, in which case difficulty is encoun tered in operating the drop in exchange #3 directly from the ringing current generated at exchange #1. For this purpose, arrangements have been provided in the toll switching selectors, such as II, for relaying ringing current in a manner to be pointed out hereinafter.

Referringt-o Figs. 26, Fig. 2 shows the line of substation A, the cord circuit CC and the left hand end of the toll line X; F 3 shows the repeater R, on the right hand end of the toll line X, and the cord circuit CC;

. Fig. 4 shows the toll first selector I, individual to the repeater R, Figs. 1 and 3, and the toll-switching second selector II; Fig. 5 shows the repeater R on the left hand end of. the toll line Y; and Fig. (ishows the repeater R on the right hand end of the toll line Y. Regarding the automatic switches shown in the drawings, it is assumed that they are of the well known vertical and rotary type with ten levels of bank contacts and ten sets of: bank contacts in each level.

The apparatus and the layout having been described in general, a detailed description of Cir lllt) lit) the operation will now be given. For this purpose it will be assumed that the toll operator in exchange #1, Fig. 2, receives a ticket calling for a connection set up from the line of substation A in exchange #1 to the line of substation A Fig. 1, in exchange #3.

Connection from emchange #1 to @50- change #3.

Upon receiving the above ticket, the toll operator in exchange #1 inserts: the plug of an idle cord circuit, for example, the left hand plug of the cord circuit CC into the jack J associated with the line of substation A, but the operatordoes not depress the ringing keyl The operator now inserts the right hand plug of the cord circuit CC into the jack of an idle toll line leading to exchange #2. Assuming that the toll line X is idle as indicated by the unoperated condition of the mechanical signal 10, the operator may insert the right hand plug of the cord circuit CC into the jack J The jack J is used in case the operator desires to set up an automatic connection over the toll line X, and the jack J is used in case the operator desires to set up a connection over the toll line X to the toll board in exchange #2.

Responsive to the insertion of the plug of the cord circuit CC into the jack J sleeve relay 6 of the cord circuit and sleeve relay 11 of the trunk energize in series. Sleeve relay 6 at armature 7 prepares a locking circuit for the ring-up relay 4. Sleeve relay 11 of the trunk cuts off the drop D at armature 13; at armature 12 closes a circuit for the busy signal .10 and its multiples at the other positions; and at armature 14 disconnects the interrupter 17 from the impulse conductor 16. As

a further result 01 the plugging in operation, the spring 9 or the'jack J connects the impulse conductor 16 to ground through the supmrvisory relay 15 and through the contacts of the associated callingdevice key. This results in a closure of a circuit from ground through relay 15 and over the impulse conductor 16 iior line relay 105 of the distantrepeater R in exchange #2. This circuit includes the two sides of the toll line X in multiple, armature 117 and its resting contact, armature 114 and its resting contact, and the normally closed contacts controlled by armature 119. Line relay 105 of the repeater R and supervisory relay 15, Fig. 2,

energize in series over this circuit and relay 15 closes a circuit for the associated supervisory lamp L In the exchange #2, line relay 105, upon energizing, closes at armature 120 a circuit for release relay 106. Release relay 106 at armature 121 disconnects release-trunk conductor 132 of the toll first selector 1, Fig. 4, from the branch leading to relays 101 and 102 and connects it to ground instead. .This opera.-

tion makes the toll line X test-busy in the banksof the toll switching selectors to which the said trunk line is accessible. At armature 123, the relay 106 closes a circuit for relay 101, which relay energizes and disconnects the conductors associated With the right hand repeating coil windings from the toll board and connects them instead to the con responding conductors of the repeater R. At armature 1.11, relay 101 disconnects sleeve conductor 143 from relay 103 and connects it instead to battery through the resistance 112. This places battery on the sleeve of the jacks J and J This brings about the operation of the associated cut-ofi relay which disconnects the drop I) from across the tip and ring conductors of the said jacks and closes a circuit for the busy signal 162 and its multiples.

At armature 122, relay 106 prepares a circuit for repeatingrelay 107, and at armature 124 itcloses a bridge across conductors 131 and 136 including the polarized relay 109 and armature 125 and its resting contact. Line relay 202 of the selector 1, Fig. 1, which is connected to conductors 131 and 136 through the resting contacts and armaturcs 219 and 223, energizes over the above traced bridge, but the polarized relay 109 does not operate the contacts 130 due to the fact that it is polarized so as not to respond to the current flow in the normal direction.

In the selector I, relay 202 closes at armature 215 a circuit for release relay 203 which energizes and prepares at armature 216 a circuit for vertical magnet 212, at the same time opening a point in the circuit of release magnet 206.

The foregoing operations have all occurred responsive to the insertion of the right hand plug of the cord CC, Fi 2, into the jack J After having inserted the plug into the jack, the operatorthrows the calling device key individual to the trunk line, thereby including the calling device CD in the circuit in. series with the supervisory relay 15.

When the calling operator dials the digit 0 necessary to extend the connection to a toll switching selector, the calling device CD interrupts the impulse circuit extending to the line relay 105 of the repeater R ten times. Line relay 105 therefore falls back ten times, and, each time it does so, it closes at armature 120 a circuit through armature 122 and its working contact for repeating relay- 107. Repeating relay 107 energizes each time its circuit is closed and it closes at armature 127 a circuit for the slowacting relay 108, which relay energizes and maintains relay' 109 shunted at armature 129 throughout the repeating of impulses to the line relay 202 of the selector 1, which repeating is accompli shed at armature 125 of relay 107. It will be noted that, upon each energization of repeating relay 107, ground is removed at 'tacts in the tenth level.

armature 128 from conductor 138, but this operation does not have any particular utility at this time.

In the toll first selector I, Fig. 4, each time line relay 202 falls back responsive to an interruption produced in its circuit at armature 125 of repeating relay 107 of the repeater R, it closes at armature 215 a circuit through the resting contact and armature 220, armature 210 and its working contact, and series relay 207, for the vertical magnet 212. By the operation of vertical-mag net 212 the wipers 224-228 are raised step by step until they come to rest opposite the tenth level oi bank contacts. The slow acting series relay 207 is maintained operated throughout the vertical movement At armature 217 relay 207 opens a point in the circuit of rotary magnet 209 and closes a circuit for the test relay 211. Relay 211 energizes and prepares at armature 218 a locking circuit for itself and an operating circuit for the rotary magnet, which locking circuit is closed through oil-normal contacts 204 and the interrupter contacts 210 as soon as the oil-normal contacts 204 operate on the first vertical step.

At the end of the vertical movement, relay 207 falls back and completes at armature 217 a circuit through the interrupter contacts 208 for rotary magnet 209 in multiple with test relay 211. Rotary magnet 208 energizes and advances the wipers of the switch into engagement with the first set of bank con- At the end of its stroke, rotary magnet 209 opens the interrupter contacts 208 and 210. -The opening of interrupter contacts 208 brings about the deenergization of rotary magnet 209, and the opening or interrupter contact-s 210 brings about the deenergization of test relay 211, unless the trunk line terminating in the first set of bank contacts is busy. If this trunk line is busy, rotary magnet 209 falls back just as though the trunk line were idle, but test wiper 225 encounters a ground potential on the test contact of the busy trunk and maintains test relay 211 locked up through armature 218 and its working contact. That being the case, when rotary magnet 209 falls back it reestablishes at interrupter contacts 210 a local circuitfor test relay 211, and it closes atinterrupter contacts 208 its own energizing circuit, with the result that said rotary magnet 209 energizes again and advances the wipers into engagement with the second set of bank contacts.

This buzzer like operation on the part of rotary magnet 209 continues until an idle trunk is reached, which trunk it will be assumed is the one terminating in bank contact 229233 and extending to the toll switching second selector 11. hen this trunk line is reached, test wiper 225 encounters an ungrounded test contact with the result that test relay 211 falls back when its locking circuit is opened at interrupter contacts 210. The seized trunk is made busy through test wiper 225 and a circuit is closed for switching relay 213 through armature 218 and its resting contact and the eleventh rotary springs 214 as soon as rotary magnet 209 falls back and again closes the interrupter contacts 210. Switching relay 213 energizes over its circuit and opens a point in the combined operating and release circuit at armature 220 connects up wiper 226 and 227 at armatures 221 and 222 and at armatures 219 and 223 disconnects conductors 131 and 136 from line relay 102 and extends them to the corresponding conductors of the seized trunk line.

The line and release relays 242 and 243 of the selector II now operate and the latter prepares a circuit for vertical magnet 254 at armature 258. V

Since the toll lines extending through we change #3 terminate at the second level of the toll switching selector II, the calling operator now dials the digit 2 with the result that the repeater B, Fig. 3, opens the circuit of line relay 242 of the selector II two times, Each time its circuit is opened, relay 242 falls back and closes at armature 257 a circuit through armature 258 and its working contact and series relay 244 for the vertical magnet 254. Vertical magnet 254 responds and raises the wipers 272-275 opposite the second level of bank contacts. Series relay 244 responds and opens a point-in the circuit of rotary magnet 252 and prepares a circuit for stepping relay 245 which is completed upon the closure of off-normal contacts 256 through the interrupter contacts 255. Stepping relay- 245 energizes and locks itself at armature 260 to ground through the resting contact and armature 265, at the same time preparing the rotary magnet circuit at armature 261.

At the end of the vertical movement, relay 244 falls back and completes at armature 259 the circuit of rotary magnet 252. Rotary magnet 252 energizes and advances the wipers into engagement with the first set of bank contacts in the second level. Near the end of its stroke, rotary magnet 252, at the interrupter contacts 255, opens the circuit of stepping relay 245 which falls back and opens at armature 261 the circuit of rotary magnet 252. Rotary magnet 252 falls back and closes its interrupter contacts 2 55 again.

In case the trunk line terminating in the first set of bank contacts is idle, switching'relay 246 energizes in a circuit including contacts 253, off-normal contacts 256, interrupter contacts 255, and stepping relay 245. However, assuming the trunk line to be busy, test wiper 273 encounters a ground potential 011 the busy test contact with th'e'result that switching relay 246 is short circuited and does not energize. Stepping relay 245 energizes through the test wiper in this case and again completes the rotary magnet circuit. The rotary magnet energizes and steps the wipers to the second set of bank contacts.

This alternate operation of the stepping relay and the rotary magnet continues until an idle trunk is reached, which trunk it will be assumed is the one comprising conductors 276-279 and extending to the repeater R, Fig.5. l/Vhen this idle trunk is reached, switching relay 246, being no longer short circuited, energizes in series with stepping relay 245, but stepping relay 245 does not operate 011 account oi? the relatively high resistance of switching relay 246. Several things happen responsive to the energization of switching relay 246 and these will now be taken up and explained one at a time.

At armature 264, relay 246 prepares an impulse circuit which will be completed subsequently at the repeater B.

At armature 265, relay 264 disconnects ground from armature 257 of line relay 242 and closes a circuit for the supervisory relay 10401? the repeater R through armature 289 and its resting contact and armature 271 and its resting contact, bank contact 232, wiper 227, working contact and armature 222, conductor 134, resting contact and armature 171, and supervisory relay 104 to battery. Supervisory relay 104 is stiflly'adjusted so that its operation does not take place immediately upon the closure of its circuit.

As a further result of its operation, switching relay 246 of the toll switching selector II disconnects the associated incoming trunk conductors from line relay 242 and extends them through the resting contacts and armatures 268 and 270 to the wipers 272 and 275 which are standing upon the bank contacts to which the conductors 276 and 279 leading to the talking conductors of the repeater R are connected.

At armature 263, relay 246 opens the test circuit of the selector and connects the grounded release trunk conductor to the test wiper 273. thereby extending a ground potential to the release trunk conductor 277 of the repeater B. This ground potential is extended through armatures 317 and its resting contact of relay 304, and armature 324 and its resting contact to relay 308. Relays 308 and 309 energize in series. Relay 309 at armatures 328 and 330 completes the talking circuit between the repeater R and the associated toll line Y, at the same time disconnecting the talking conductors extending to the manual switchboard, and armature 329 disconnects the sleeve relay 307 and places battery through the resistance 312 on the sleeve of the jacks at the toll board. The sleeve relay at the toll board now operates and closes a circuit for the multipled busy signals and cuts olf the associated drop.

308at armature-326 disconnects the impulse conductor associated with the right hand repeating coil winding from line relay 305 and connects it instead to the incoming impulse conductor 278, and at armature 327 closes a circuit for the switching relay (not shown) of the toll first selector 1 This circuit may be understood upon reference to Figs. 3 and 4, as it corresponds to a circuit closed on the energization of relay 102 at armature 115 and over conductor 135 for the switching relay 213 of the selector I. Accordingly, the switching relayof the selector I pulls up and cuts-oil? the associated line relay.

The above circuit change at armature 326 of relay 308 results in the closure of the impulsing circuit which was previously prepared at armature 264 of switching relay 246 of the selector II. This impulsing circuit is as follows: from ground by way of the resting contact and armature 128 of the repeating relay 107 in the repeater B, Fig. 3, conductor 133, armature 221 and its working contact, wiper 226, bank contact 231, armature 264 and its workingcontact, resting contact and armature 288, supervisory relay 249, wiper 274, the bank contact on which it is standing, conductor 278, working contact and armature 326 of relay 308 in the repeater It. Fig. 5, resting contact and armature 325, right hand repeating coil windings, the two conductors of the toll line Y in parallel, left hand repeating coil windings, Fig. 6, armature 419 and its resting contact, armature 416 and its resting contact, normally closed contacts controlled by armature 421., and line relay405 of the repeater R to battery- Supervisory relay 249, Fig. 4, and line relay 405, Fig. 6, operates in series over this circuit. At armature 271., relay 249 opens the previ ously traced circuit of the stifliy adjusted supervisory relay 104 of the repeater R, before the said relay has had time to operate responsive to the closure of its circuit at armature 265 of relay 246, Fig. 4. It may be pointed out at this time, however, that no serious harm would result if relay 104 did operate prior to the above opening of its circuit at armature 269 of supervisory relay 248, F ig. 4, as it would fall back again upon the alcove opening of its circuit.

In the exchange #3, line relay 405 oi the repeater R Fig. 6, upon energizing, closes a circuit for release relay 406, which relay energizes with results similar to those described in connect-ion with the energization of relay 106 of the repeater R, 3. Briefly, the release trunk conductor extending to the associated selector 1* is grounded; relay 401 energizes with the result that points are closed in the talking circuit and the trunk is made busy at the toll board; and a bridge is closed at armature 406 through the polarized relay 409 across the talking conductors leading to the associated. 'zol], first selector 1*. This latter operation results in the selector I being prepared for operation in the hereinbefore described manner.

It may be pointed out at this time that the current flow in the back bridge of the repeater R and in the control loop extending ahead through the selector I to the selector II has ceased and that the control for setting up and releasing the remaining part of the connection is exercised over the separate control circuit, above traced, including conductor 133, Fig. 3. This leaves the loop circuit free for then subsequent passage of ringing current which is to be relayed at the selector II.

The calling operator now turns her calling device in accordance with the thousands digit 9 in the desired number with the result that the repeating relay 107 in the repeater B, Fig. 3, is energized nine times momentarily in the hereinbefore described manner. The opening of the upper talking conductor at armature 125 does not have any effect at this time owing to the fact that the talking conductors are at this time free from current flow. Each time it energizes momentarily, relay 107 opens at armature 128 the previously traced circuit for line relay 405 of the repeater R Fig. 6, which circuit extends through the selectors I and II, through the repeater R, and over the toll line Y. Line relay 405 responds to the nine interruptions produced in its circuit and energizes the as sociated repeating relay 407 nine times momentarily, with the result that armature 427 produces nine interruptions in the circuitof the line relay (not shown) of the associated toll first selector 1*. The result is that the said first selector I Fig. 1, raises its wipers opposite the ninth level and extends the connections to an idle second selector, for ex ample, the second selector I1 Fig. 1. It will be noted that the slow acting relay 408 of the repeater R maintains the polarized relay 409 short circuited at armature 430 during the repeating of impulses so as to improve the impulsing circuit.

Supervisory relay 249, Fig. 4, which is included in the impulsing circuit controlled at armature 128 by repeating relay 107, Fig. 3, may fall back during the repeating operation, but this is immaterial as a point in the supervisory circuit controlled by relay 249 is maintained open atarmature 171 of relay 108, Fig. 3.

When the calling operator dials the remaining three digits 1 1 and 0 a number of the desired subscriber the secondselector I1 and a connector, C for example, operated to complete the connection. The connector C automatically transmits ringing current periodically to signal the subscriber at substation A in the usual manner.

After having completed dialling the numher, the calling operator restores the calling device key thereby freeing her ealling'device for use in connection with another toll line.

\Vhen the called subscriber responds to the ringing of his bell by removing his receiver, the connector C, Fig. 1 removes the ringing current in the usual manner and connects up the usual back-bridge relay which energizes over the calledv line and reverses the direction of current flow in the portion of the connection in extending back through the selectors II and I to the repeater R When this occurs, the polarized relay 409,Fig. 6,at contacts 431, closes a circuit for the supervisory relay 404. Relay 404 energizes and at armature 421 closes a local circuit for line relay 405 through resistance 411, at the same time disconnecting line-relay 405 from the incoming control circuit including the two conductors of the toll line Y in multiple. Supervisory relay 249, Fig. 4, now restores and closes at armature 271 the previously traced circuit through bank contacts 232 and wiper 227 for relay 104, Fig. 3; Relay 104 operates and closes a local holding circuit for line relay 105 at the same time opening the initial circuit. When this occurs, the supervisory relay 15, Fig. 2, falls back and extinguishes the super visory lamp L thereby giving the calling operator answering supervision.

The toll operator may now converse with the called subscriber and, upon ascertaining that the desired line has been reached, request him to Wait a moment, whereupon the open ator throws theringing key K associated with the left hand end of the cord circuit CC, thereby recalling the calling subscriber.

When the calling subscriber removes his receiver, the talking connection is complete between the calling and called substations, and the conversation may proceed as desired.

lVhen the conversation is terminated, the two subscribers replace their receivers. The supervisory lamp L associated with the left hand end of the cord circuit CC becomes lighted when the subscriber at substation A replaces his receiver.

When the receiver is replaced at the called substation the back-ridge relay (not shown) of the connector C", 1, falls back and reverses the current fiow in the associated con.- ductors to normal, with the result that the polarized relay 409, Fig. 6, retracts its armature and opens the circuit of relay 404. Relay 404 falls back and closes the initial circuit of line relay 405 over the toll line Y, at the same time opening the local circuit including the resistance 411.

In the exchange #2, supervisory relay 249, Fig. 4, pulls up and opens at armature 271 the circuit of relay 104 of the repeater B, Fig. 3. Relay 104 falls back and reestablishes the original. circuit of line relay 105 over the toll line X, at the same time opening the local holding circuit.

In the calling exchange, supervisory relay 15 again energizes and closes a circuit for the associated supervisory lamp L Upon perceiving the disconnect signal from both subscribers, the toll operator pulls down the connection.

lVhen the plug of the cord circuit CC is removed from the jack J, sleeve relay 6 ot the cord circuit CC and sleeve relay 11 associated with the ElUli J" both fall back. At armature 13, relay 11 reconnects the drop I) across the tip and ring conductors of the jack J and at armature 12 it opens the circuit of the visual signal and its multiples. As a further result of the removal of the plug from the jack, the branch 16 of the impulse circuit close over the toll line X is disconnected from ground through the supervisory relay and is reconnected to battery through armature 14 and its resting contact and the interrupter 14. This results in the deenergization of line relay 105 of the repeater R, Fig. 3. Upon falling back, relay 105 opens the circuit of the slow acting release relay 106 at armature 120 and closes a circuit through armature 122 and its working contact for repeating relay 107. Repeating relay 107 energizes and closes at armature 127 a circuit for the associated slow acting relay 108 which relay energizes and opens at armature 171 a point in the circuit of supervisory relay 104. Repeating relay 107 also opens at armature 128 the impulse circuit extending through the established connection including supervisory relay 249 of the selector II, Fig. 4, to the line relay 405 of the repeater R Fig. 6. When this occurs relay 249, Fig. 4, and the said line relay both fall back. Relay 249 at armature 271 closes a point in the previously traced circuit of supervisory relay 104 of the repeater R, but relay 104 does not operate on account of the fact that a point in its circuit is now open at armature 171 of relay 108.

After the interval for which it is adjusted, the slow acting release relay 106 falls back and opens the circuit of relay 101 at armature 128, at the same time removing ground from the release trunk conductor 132 at armature 121, and opening at arn'iature 122 the circuit of repeating) relay 107.

Rcsponsivc to the removal of ground from the release trunk conductor 132, switching relay 213 of the selector I, switching relay 246 of the selector II, and relays 308 and ot the repeater R all fall back. The doc-nergization. of switching relays 213 and 246 results in the energization of theassociated release magnets 206 and 250 through oil-normal contacts 205 and 251, respectively. The release oi" these two selectors now takes place in the usual manner.

In the repeater R, the deenergization of relays 308 and 309 results in the associated circuits being restored to their normal position.

. trunk conductor at armature 425 with the result that the intervening selectors are restored to their normal position in the usual. manner. Relay 401 falls back and restores the circuits associated with the jacks J and J to normal.

The connection is now completely released and the apparatus employed therein is now in readiness to be used in setting up subsequent connections.

Alt rnative handling of preceding col-mew tion.

It will now be fiSSt'lll'lGd, that the subscriber at substation A, Fig. 2, desires to converse with a subscriber whose line terminates in exchange #3; but the calling subscriber does not know'the number or" the desired line, knowing only the name and location 01'? the subscriber; and that the toll operator in exchange i tl is unable to find out the number from her records. In this case the calling toll operator proceeds as before to extend a connection to a toll line leading to exchange #3 after which she throws her ringing key and signals the toll operator in exchange #3. The calling toll operator then transmits the necessary information to the toll operator in exchange #3, who completes the connection from her switchboard to the called line through the regular automatic switch train. The manner in which this is accomplished will now be pointed out.

rissuming that the toll operator at the switch board shown in Fig. 2, has taken the toll line X for use and has extended the connection through the repeater R, the selectors I and II, the repeater i. and the toll line Y to the repeater R Fig. 6 the hereinbefore described circuit for line relay 405 of the repeater R is closed from armature 128 of repeating relay 107 of the repeater R, Fig. 3. The energization of line relay 405 results in the energization of re lease relay 406, which closes at armature 425 a circuit for relay 401 which accordingly energizes with the results pointed out hereinbetore.

The calling operator now throws the combined listening and ringing key K of the cord circuit CC into the ringing position. This results in the transmission of ringing current over the established connection. In order to insure the reliable operation of the'drop on lllt) Ill) It will be reineinbered that the drop D Fig. 6, is cut oil at armature 413 and 415 of relay 401 and at the cutoff relay at the toll board. Accordingly. the control circuit extending to exchange #3 over the toll line Y must be opened in order to secure the reconnection of the drop to the right hand repeating coil windings before the drop can be operated. That being the case, the repeating relay 248, Fig. 4, closes at armature 269 a circuit for relay 280. Relay 280 energizes and closes a locking circuit for itself at armature 289, at the same time opening a point in thecircuit of supervisory relay 104, Fig. 3. At armature 288, relay 280 opens the impulse circuit extending through the repeater R to the toll line Y, whereupon supervisory relay 249 of the selector II and the line relay of the repeater R Fig. 6, both fall back. Supervisory relay 249, Fig. 4, closes at armature 271 a point in the circuit of supervisory relay 104, Fig. 3, but the latter relay does not operate owing to the fact that a point has been opened in its circuit at armature 289 of relay 280.

In the repeater B", Fig. 6, line relay 405 falls back, followed by the deenergization of relay 406 which opens the circuit of relay 401.- Relay 406 also removes ground from the associated release trunk conductor at armature 423, and opens the bridge across the outgoing talking conductors at armature 426. Relay 401 on falling back connects up the tip and ring conductors of the jacks J and J to the right hand repeating coil windings, and at armature 414 opens the circuit of the cut oil relay at the toll board. The cut oil relay falls back and connects up the associated drop, with the result that the drop D responds to the ringing current.

hen the calling operator restores the ringi ng key K, Fig. 2. the ringing response relay 247, Fig. 4, falls back, tollowed by the deencrgization of the associated slow acting relay 248. Relay 248 removes the local source of ringing current at the same time again closing the associated points in the talking circuit. At armature 269, relay 248 opens the initial circuit of relay 280, but relay 280 remains locked up at armature 289.

When the operator in exchange #3 notes the operated condition of the 'drop 1), she inserts the plug of an idle cord clrcuit (corresponding to the left hand plug of the cord circuit CO, Fig. 3,) into the jack J This results in the energization of the sleeve relay associated with the jacl: and in the energization over a circuit through armature 414 and its resting contact of relay 408 of the repeater. Responsive to the energization of the sleeve relay associated with the jack J, the drop I) is cut oil and the usual busy circuit is closed.

Responsive to the energization of relay 403 in the repeater R the release trunk conductor extending to the associated selector 1* (not shown) is grounded at armature 418. Also the impulse conductor associated with the mid-point of the left hand repeating coil windings is disconnected at armature 419 from line relay 405 and is connected instead to ground, the impulse conductor leading to the top contact of the jack J This latter operation however is without any particular effect at this time owing to the fact that the impulse circuit is open at the distant end of the toll. line Y.

The two operators may now converse with each other.

Upon learning the facts from the calling operator, the operator in exchange #3 looks up the number of the desired subscriber, and inserts the other plug of the cord circuit in use (corresponding to the right hand plug of the cord CC, Fig. 3,) into the jack J with the result that the line and release relays of the selector I operate and prepare the switch for operation in the usual manner.

The operator in exchange #3 now connects her calling device with the right hand plug of the cord circuit in use and dials the digits in the number of the desired line, with the result that the connection is extended in the usual manner. V

The calling operator in exchange #1, Fig. 2, maintainsher listening key operated and she converses with the called subscriber when he responds, after which she signals the calling subscriber to tell him that the connection is completed.

When the conversation is completed, the two subscribers replace their receivers. disconnect signal is given to the toll operator in exchange #1, when the calling subscriber hangs up, and a disconnect signal is given to the operator in exchange #3 when the called subscriber hangs up. Either operator pulls down the associated cord circuit when she receives the disconnect signal.

Then the operator in exchange #3 pulls down the connection'by' removing the plugs "from thejacks J and J, the circuits associated with the repeater R restore to their normal position, and the switches in exchange #3 release in theusual manner.

lVhen the toll operator in exchange #1 pulls down the connection, the toll line X is freed in exchange #2 and the selectors I and II, Fig. 4., are released in the hereinbefore described manner.

it may be pointed out that in case the toll operator in exchange #1 pulls down the connection ahead of the toll operator in exchange #3. the toll line X is freed as before and the selectors I and II, Fig. 1, both release, but the toll line Y is held busy in exchange because of the plug being in the jack J Fig. 6. In this case, the line relay 305 of the repeater R, Fig. 5 energizes over the toll line Y in series with the supervisory relay associated with the jack J Fig. 6, with the result that the toll line Y is guarded against seizure in exchange #2. The supervisory relay associated, with the jack J Fig. 6, closes a circuit for the lamp L which becomes lighted and gives the toll operator a further indication of the fact that the conversation is over and the connection may be pulled down. The circuits restore to their normal position and the switches in exchange #3 release as before when the toll operator in exchange #3 finally pulls down the con nection.

0012010065072 from archway c #1 to ca:-

GZ'fL/lf/(i Assuming now that the toll operator in exchange #1 receives a ticket calling for a connection set-up from the line at substation A to a line terminating in exchange #2, the toll operator proceeds as in the previous case except that this time she merely dials the local designation of the line in exchange #2, as the first nine levels of the selector 1. Fig. 1, are multiplied with the corresponding levels of the first selectors in exchangeas may be seen in Fig. 1.

When the called subscriber answers, the polarized relay 109 of the repeater B, Fig. 3, (assuming that the toll line X is used) closes at contacts 130 a circuit for the supervisory relay 10 1. Relay 10-1 energizes and closes a local. circuitfor line relay 105, at the same time opening the impulse circuit over the toll line X.

Supervisory relay 15, Fig. 2, now falls back and opens the circuit of the associated supervisory lamp L giving the calling operatoranswering supervision.

The calling operator may now proceed as before to ascertain if the line called is the wanted line and, if so, to recall the subscriber at substation A.

lVhen the conversation is terminated, the two subscribers replace their receivers with the result that the toll operator gets a disconnect signal from each subscriber and she pulls down the connection. The disconnect signal from the called subscriber is received owing to the opening of the circuit of supervisory relay 101 by the polarized relay 109, Fig. 3. The automatic switches in exchange #2 release responsive to the lOlTlOVfll of ground from release trunk conductor 132 at armature 121 of release relay 106.

A Harriet Zoe lac n (Mag 0 f preceding 00nmotion.

Assuming now that the toll operator in exchange #1 receives a ticket calling for a connection between a local line and the line of the subscriber in exchange #2 whose number Vl lien the calling operator throws her ringing key, the drop I), Fig. 3, is operated in the usual manner.

When the toll operator in exchange #2 notes the operated condition of the drop D, she inserts the plug of an idle cord circuit, for example, the left hand plug of the cord circuit: CC, into the jack J By this operation theassociated sleeve relay closes the usual busy circuit and cuts off the drop D, and the sleeve relay 108 in the repeater R energizes through armature 111 and its resting contact, and makes the trunk line X busy to the toll switching selectors by applying ground potential armature 116 to the release trunk conductor 132. Sleeve relay 163 of the cord circuit CC energizes and at armature 165 prepares a locking circuit for relay 164.

Upon being informed of the facts known as to the line wanted, the toll operator in exchange #2 looks up the number and proceeds to complete the connection. In order to do this. she inserts the right hand plug of the cord circuit CC into the jack J This results in the energization of the line relay 202 of the first selector I in series with the polarized supervisory relay 165 of the cord circuit. A circuit is closed at armature 215 of the line relay of the selector for the associated release relay, whereupon the selector is prepared foroperation in the usual manner.

Polarized relay 165 of the cord circuit CC operates to close a circuit for the associated supervisory lamp L at this time owing to the fact that itis polarized so as to operate with the eurrentfiow in its normal direction.

The tool operator in exchange #2 now throws the combined calling device and'ringing key K in the proper direction to connect up the callin device CD After which she dials the digits in the desired number (and then restores her key) With the result that the connection is set up to the called line in the usual manner.

When the called subscriber responds, the current flow is reversed and the polarized supervisory relay 165 retracts its armature and extinguishes the supervisory lamp L may restore her listening key and depend upon a recall from the toll operator in exchange #2. In this latter case, the toll op erator in exchange #2 momentarily operates the key K to project ringing current out over the toll line X with the result that the ringing response relay 1 associated with the right hand end of the cord circuit CC operates and closes a locking circuit for itself at armature 5. The supervisory lamp L becomes lighted in multiple with the locking winding of relay 4.

Upon noting the lighted condition of the lamp L, the toll operator in exchange #1 throws her listening key, whereupon relay 4 falls back and the lamp L becomes extinguished.

The operator in exchange #1, upon learning that the called subscriber has responded, recalls the calling subscriber in the usual manner.

When the conversation is terminated, the toll operator in exchange #1. receives a disconnect signal from the calling subscriber, and the toll operator in exchange #2 receives a disconnect signal from the called subscriber due to the reoperation of the polarized relay 105. Fig. 3, when the direction of the current flow in the calling loop is restored to normal.

The two operators now remove their respective plugs from the jacks, whereupon the circuits restore to their normal position and the switches in exchange #2 release.

Regarding the manner in which the toll operator in exchange #2 sets up connections including local lines as calling lines, it may be pointed out that in case the cord circuit CC is used, the toll operator first places the left hand plug of this cord circuit into a jack associated with atoll line, for example the jack J ot the toll line X, in case the desired subscriber is in exchange #1, so as to take the toll line for use and guard it against seizure by the automatic switches incase #2. Having done this, the operator inserts the 'right hand plug of the cord circuit into the local jack associated with the same toll line, for example, the jack J and dials the digits in the number of the calling subscriber except the last digit. V The calling toll operator now signals the toll operator in exchange #1, who sets up the connection to the desired called line. hen this has been done the calling toll operator dials the final digit in the number of the calling subscriber to complete the connection.

When the calling subscriber responds, the polarized relay in the calling toll operators cord circuit extinguishes the associated supervisory. lamp in the usual manner.

The automatic switches release when the toll operators remove the plugs of the cord circuit at the end-oi the conversation.

It will be noted that the toll line X is pro vided with two acks J and J Fig. 3, at the toll board and that the calling device Cl) may be connected up in the simplex operated conductor of the toll line X in series with the supervised relay 161. It is to he understood, however, that as long as exchange #1 is operated manually the provision of two jacks is unnecessary. The full equipment is shown in connection with the right hand end of the toll line X. however. so that in case the exchange #1 is converted to automatic operation there need be no change in exchange #2.

It may be noted at this point that as long as exchange #1 is a manual exchange it is immaterial which of the two jacks J and J the toll operator in exchange #2 uses in setting up a connection to exchange #1, but in case exchange #1 is converted to automatic operation the toll operator must use the jack J to originate a call over the toll line to prevent the distant drop D from being cut cit in the manner explained in connection with calls originated in exchange #1.

It is though that the manner in which the toll operator in exchange #2 sets up connections from local lines to lines terminating in exchange will he readily apparent from the foregoing.

Certain points in connection with calls originated by the toll operator in exchange #3, will now be considered. 7

Assuming that the toll '(ugerator in exchange #3 is ordered to set up a connection from a calling line in exchange #3 to a line in. exchange #2, to signal the operator in exchange #2 she may use the alternate jack ot' a toll line, for example jack J of the toll line Y. with the result that no control circuit stablished over the toll line and the drop D Fig. 5, remains connected up and is operated when the calling toll operator throws her ringing key. I

Assuming that the toll operator in exchange #3 knows the number of the desired line in exchange #2. she inserts the calling plug of her cord circuit into the automatic jack of a toll line. for example, the act: J Fig. 6, which results in the closure of a cir cuit previously trace-d. including the supervisory relay associated with the jack J and line relay 305 of the repeater B, Fig. The supervisory relay lights the associated supervisory lamp L and the operation of the line relay of the repeater B, Fig. 5, results in the usual circuit changes and in the preparation for operation of the associated toll first sclector I Responsive to the dialling of the digits in the number of the desired line, the connection is set up to the desired line in a manner hereinbefore described.

ln case the toll operator in exchange #3, sets up a connection from a local calling line to a desired line in exchange #1, a certain new operation comes into play. Since it is not optional on the part of the calling operator at this time whether she shall dial the complete desire l number or signal the operator in the called exchange (the called exchange being a manual exchange), arrangements have been provided to remind the calling toll operator that she must signal the distant operator as the called exchange is a man ual exchange. The manner in which this is brought about will now be explained.

Assuming that a connection is set up from the toll line Y to the toll line X including the toll first selector P, Fig. 1, and the toll second selector 11, Figs. 1 and 4, corresponding to the connection set up in the reversed direct-ion and including the circuit drawings shown in Fig. 4, a circuit is completed extending from ground at armature ot relay 302 Fig. 5, through the toll first selector It, and thence through the supervisory relay circuit of the selector 11, Fig. t, to the incoming impulse conductor 183 of the repeater it, 3. Upon the energization of relay 1.02 of the repeater R, which takes place upon the seizure of the repeater, this circuit is extended through the working contact and armature 111-1, and the resting contact and armature 117, out over the two sides of the toll line X in parallel, and is completed to battery through conductor 16, Fig. 2, arn'iature 1st and its resting contact. and the interrupter 17. Each time the interrupter 17 is closed, it supplies battery to the above circuit, and supervisory relay 24-9, Fig. l, is operated and opens the circuit of the supervisory relay 306, Fig. 5, at arn'iature 271, and, each time the circuit is opened by the interrupter, supervisory relay 24:9 falls back and completes the circuit of relay 306 at armature 271. Relay 306 pulls up and closes a local circuit for relay 305, at the same time opening the initial circuit of relay 305. This results in the deenergization of the supervisoryrelay associated with the toll line Y in Fig. (2, and in the lamp If being extinguished. As the interrupter 17, Fig. 2, operates, the lamp L Fig. 6, flashes in unison, indicating to the calling operator that the called exchange is a manual exchange.

In case the calling operator should wish to release the established connection without signalling the operator in the called exchange, the connection can be released only during a closure of the interrupter in exchange #1, as when the interrupter is open, the connection is locked up locally in exchange #2, by relay 306, Fig. That being the case, the operations of the interrupter 17 are such that battery is ap lied for a suiiiciently long interval to ena ile the release to take place in case the calling operator withdraws her plug without signalling.

Assuming tl'lat -the calling operator rings the distantoperator, the action. of the ringing current repeating portion of the selector Ill, Fig. 4, results in a permanent opening of the impulsing circuit and in an opening of the circuit oi? the supervisory relay in the repeater B, Fig. 5, in a manner similar to that pointed out hereinbel ore in -connection with a call in the reverse direction. When this occurs, the calling supervisory lamp becomes lighted steadily and the connection may be released at any time.

If desired, the connection at the manual exchange, Fig. 2, including the interrupter l7 could be omitted in which case a calling operator in exchange #3, would be reminded that exchange #1 is a manual exchange by an extinguishing of her supervisory lamp immediately after the dialling of the exchange digits. In this latter case, however, the connection would be automatically locked, up upon its completion to the manual exchange owing to the fact that no control circuit would be closed over the toll line X, and the calling operator could not secure the release of the automatic switches b merely withdrawing her plug, but would have to first ring out over the toll line Y to secure the above operation of the ringing-currentrepeating portion of the selector II, Fig. 4, to unlock the connection above pointed out.

It is sometimes desired to operate part of the toll lines outgoing from exchange #2 to an outlying exchange manually as regards calls incoming to the outlying exchan 'c, while other toll lines connecting the same two exchanges are arranged for full automatic operation. In order to inform a calling toll operator of the character of the toll lines in either case, those that are arranged for part manual. operation have their impulse circuits normally open in the outlying exchange or connected to an interrupter as shown in Fig. 2.

lVhat is claimedv is: v

l. in a telephone system, means including two automatic switches in serial relation for setting up a connection, a repeater, a control circuit for the first of said automatic switches extending from said repeater, a parallel control circuit separate from said first control circuit extending from the repeater through the connection set up by the first switch to the second switch, and means for operating said switches over their respective control circuits.

2. In a telephone system, an incoming line terminating at an automatic impulse repeater, two automatic switches, means in said repeater responsive to control over said incoming lines for operating the first of said automatic switches to extend a connection to theseeond switch, and means in said repeat-er also responsive to control over said incoming line for operating said second automatic switch over a circuit path including the connection set up by said first switch and excluding the control circuit between said rcpea'ter and said first switch.

' 3. in a telephone system, two conductors extending to an automatic switch, a second automatic switch, means in said first automatic switch controlled over only one ot' said conductors to extend both ot said conductors to said second automatic switch, and means controlled over only the other of said conductors for operating said second automatic switch.

t. In a telephone system, a trunk line ineluding a pair of talking conductors and a separate control conductor terminating in an automatic switch, a second automatic switch, means controlled over said talking conductors to operate the first named automatic switch to set up a connection to said second autom atic switch includin the talking conductors of said line and said separate control conductor, and means-controlled over said separate control conductor for operating said second automatic switch.

5. In a telephone system, two exchanges, a trunk line extending from the first exchange to the second exchange, a manual switchboard at said second exchange, a branch of said trunk line extending to said manual switchboard, a ringing response device associated with said branch, automatic switching mechanism in the second exchange responsive to control over said trunk line, means in the first exchange for extending a connection to said trunk line and for closing a switch control circuit thereover, means in the second exchange responsive to the closure of said switch control circuit to disconnect said ring ing response device from said trunk line, means for applying ringing current to the first exchange end of said trunk line to opcrate the ringing response device in the second exchange, and means responsive to said ringing current to open said control circuit to effect the reconnection of said ringing response device to said trunk line.

6. In a telephone system, a trunk line divided into two sections, means including said trunk line and automatic switching mechanism for setting up a telephone connection from a manual switchboard, a control circuit established over the first section, a switch control circuit established over the second section. and controlled by said first control circuit during the setting up of said connection, means eitective upon the response of the called subscriber for opening said switch control circuit, means responsive to the opening of said switch control circuit for giving supervision to the calling operator by'opening the first control circuit and 't'or closing a local holdii'ig circuit for said switching mechanism independent of the first control circuit, means etlective in another connection responsive to;

ringing current transn'iitted over said trunk line prior to the answering ot the called subscriber for opening said switch control circuit and for preventing the opening of the first control circuit and for preventing the closure of said local holding circuit;

t ll 't" -tl'l' 4. in a r epione sys em, a lllllr .mc ex tending to an impulse repeater, a control conductor extend 111g therefrom, a train of automatic switches operated over said control conductor by said repeater, when the same responds to nnpulses over said trunk line, to

, set up a connection to a called line, a super isory relay in said repeater torimposing a supervisory condition on said trunk line, a

sirpervisorvcontrol relay in one of said switches responsive to control from the called line over said control conductor, and a separate supervisory conductor extending through the established connection from the.

established over said trunk line during the course of setting up said connection, a switch control circuit controlled by the first control circuit, means etlective upon the responseot the called subscriber for opening said switch control circuit, means responsive to such opening for locking said automatic switches in operated position independent 01. the first control circuit and for opening the same, means effective when thecalled subscriber replaces his receiver for again closing said control circuit to bring about the unlocking of said switches and the reclosure of the first control circuit, means controlled by the calling party for opening the first control circuit to secure the release of said automatic switches and to open said switch control circuit, and means operative in the latter case for preventing the opening of said switch control circuit from resulting in the locking of said automatic switches.

9. In a telephone system, a first automatic switch, a group of second automatic switches, means for establishing two control circuits to the first switch, means in the first switch dircctively controlled over one out the control circuits for extending a connection to a desired one of the group of'sccond automatic switches, and means for dircctively controlling the selected second switch over the other control circuit.

10. In a telephone system, an impulse repeater, an automatic switch connected in series with. the repeater, a second automatic switch, means in the first switch controlled over a circuit extending from the repeater for operating the first switch to extend a connection to the second switch, and means in the second switch controlled over a circuit extending from the repeater and exclusive oi the first circuit for operating the second switch.

11. In a telephone system, a control device, an automatic switch connected in series with the control device, a second automatic switch, means in the first switch controlled over a circuit-extending from the control device for operating the first switch to extend a connection to the second switch, and means in the second switch controlled over a circuit extending from the control device and exclusive ot the first circuit for operating the second switch.

in a telephone system, a control device, an automatic switch connected in series with the control device, a second. automatic switch, means in the first switch controlled over a cir uit extendinglrom the control device for operating the first switch to extend a connection to lhc second switch, means in the second switch controlled over a circuit extending from the control device and exclusive of the first circuit for operating the second switch, and means for rendering the first mentioned circuit ineliective and the second mentioned circuit eii'ectivez 13. in a telephone system, a first and a second toll line, an automatic switch, means for establishing two control circuits to the automatic switch, both oi? said circuits being con trolled over the first oi. said toll lines, means tor o ierating the switch over one of said circuits to extend a connection between the two toll lilies, an automatic switch accessible by way of the second toll line, and means l'or controlling the last mentioned automatic switch over the other control circuit.

14. In a telephone system, a control device, an automatic switch connected in series therewith, a second automatic switch, means in the first switch controlled over a circuit extending from the control device for operating the first switch to extend a connection to the second switch, a third switch, means in the second switch controlled over a portion of the above circuit for extending a connection to the third switch, and means for operating the third switch over a circuit extending from the control device and exclusive of the first circuit.

15. In a telephone system a toll line, a repeater and an automatic switch connected in series therewith, a second toll line acccessible to the automatic switch, means for dialling simplex over the toll line to the repeater, means in the repeater for repeating the impulses to the automatic switch by the loop system, and means in the repeater for repeating the impulses directly to the second toll line in accordance with the simplex'system of dialling.

16. In a toll switching system, an intermediate exchange comprising automatic toll switches, incoming and outgoing toll lines at said exchange, means for controlling a plurality 01 said switches over an incoming toll line to connectthe same with an outgoing toll line, and means individual to the incoming toll line for repeating impulses from the in coming toll line directly to the connected outgoing toll line.

17. In a toll switching system, an intermediate exchange comprising automatic toll switches, incoming and outgoing toll lines at said exchange, means for controlling a plurality of said switches over an incoming toll line to connect the same with an outgoing toll line, a control circuit superimposed on said outgoing toll line, said circuit extending back through said plurality of switches after the toll lines are connected, and means associated with the incoming toll line for repeating impulses into said circuit.

18. In a toll switching system, an intermediateexchange com n'ising automatic toll switches, incoming and outgoing toll. lines at said exchange, means for controlling a plurality of said switches over an incoming toll line to connect the same with an outgoing toll line, said connection comprising two talking conductors,a control circuit built up by the operation of said switches for use in controlling other switches at the distant end of said out-going toll line, said control circuit excluding said talking conductors,,and means for repeating impulses directly from the incoming toll line to said control circuit.

19. In a telephone system, three exchanges, a trunk connecting the first exchange with the second exchange, a trunk connecting the second exchange with the third exchange, the end of the trunk terminating in the third exchange having two branches, an operators switchboard, an automatic switch, said branches terminating at said switchboard and said switch respectively, means for extending a connection from the first to the third exchange by way of said trunks, means responsive to the seizure of the second mentioned trunk for preparing a control circuit for the automatic switch, means in the first exchange for controlling said circuit or for projecting ringing current over the trunk extending from that exchange, a ringing current responsive device, and means effective responsive to the actuation of said device for opening the control circuit and for establishing a signalling circuit for signalling the operator at the third exchange.

20. A structure such as defined in claim 19, characterized in this, that the ringing current responsive device is located at the second exchange.

21. A structure such as defined in claim 19,

characterized in this, that the control circuit is superimposed on the talking conductors of the second mentioned trunk line.

22. In a telephone system, three exchanges, a trunk connecting the first exchange with the second exchange, a trunk connecting the second exchange with the third exchange, the end of the trunk terminating in the third exchange having two branches, an operators switchboard, an automatic switch, said branches terminating at said switchboard and said switch respectively, means for extending a connection from the first to the third exchange by way of said trunks, means responsive to the seizure of the second mentioned trunk for preparing a control circuit for the automatic switch, means in the first exchange for controlling said circuit or for projecting ringing current over the trunk extending from that exchange, a ringing current responsive device, means effective responsive to the actuation of said device for opening the control circuit and for establishing a signalling circuit for signalling the operator at the third exchange, a supervisory relay, and means controlled by said ringing current responsive device for rendering the relay unresponsive. f

23. In a telephone system, a first automatic switch having access to a second automatic switch and a third automatic switch, respectively, a control device, means operated under the control of said control device for setting up a connection through said first automatic switch to either of the said switches to which it has access, and means controlled from the control point for operating the seized switch over a control circuit of one character extended through the connection set up if the switch seized is the second switch and for operating the seized switch over a control circuit ofa different character extending through the connection set up if the seized switch is the third switch.

24. In a telephone system, acontrol device, an automatic switch, a plurality of conductors, including two talking conductors, extending from the control device to said switch, a second automatic'switch, a third automatic switch, means for operating the first automatic switch to seize either of the other two switches, means in the seized automatic switch, in case it is the second switch, cont-rolled over a circuit including the two talking conductors in series and extending from said control device to the switch being controlled for directively operating the switch to still further extend the connection, and means in the seized switch, in case it is the third switch, controlled over a control circuit which does not include the two talking conductors in series for directively operating the switch to still further extend the connection.

25. In a telephone system, means includ ing two automatic switches in serial relation for setting'up a. connection, a control device, a control circuit for the first of said auto matic switches extending from said control device, a parallel control circuit separate from said first control circuit extending from the control device through the connection set up by the first switch to the second switch, and means for operating said switches over their respective control circuits.

26. In a telephone system, an incoming line terminating at an automatic impulse repeater, two automatic switches, means in said repeater responsive to control over said in coming line for operating the first of said automatic switches to extend a connection to the second switch, and means in said repeater also responsive to central over said incoming line for operating said second automatic switch over a circuit path etxending from said repeater, and including the connection set up by said first switch, and excluding the control circuit between said repeater and said first switch.

In witness whereof, I hereunto subscribe my name this 20th day of April, A. D. 1926.

RALPH LEIGH RAYMOND. 

